CDI Daily Rate

Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

Annotations already declare readOnlyHint=true and destructiveHint=false, covering safety. The description adds that the tool returns 'last N observations' from BCB SGS, which reinforces idempotency and read-only nature. However, no additional behavioral traits (e.g., rate updates frequency) are disclosed.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Is the description appropriately sized, front-loaded, and free of redundancy?

The description is a single sentence that efficiently conveys purpose, data source, and license. It is front-loaded with the key information and contains no extraneous details.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

Given the output schema exists and the tool has only one simple parameter, the description adequately covers the purpose, source, and license. It could mention the annualization convention, but that is not essential for basic usage.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

Schema description coverage is 100% with detailed parameter info (default 30, max 500, daily vs monthly context). The tool description adds no further meaning, so baseline 3 is appropriate.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Does the description clearly state what the tool does and how it differs from similar tools?

The description clearly states the tool retrieves the Brazilian CDI daily rate (series 12) from BCB SGS, specifying the data source and license. It uses specific verbs ('rate') and resource ('daily rate') and distinguishes from other finance tools that may handle different series or currencies.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Does the description explain when to use this tool, when not to, or what alternatives exist?

No explicit when-to-use or alternative guidance is provided. Among siblings like finance.bcb.ipca or finance.bcb.selic, there is no indication why one would choose this CDI tool over others. The description only implies usage for CDI rate retrieval but does not clarify context.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.